Display screen or portion thereof with an animated graphical user interface



FIG. 1 is a front view of the first image in a sequence for a display screen or portion thereof with an animated graphical user interface showing our new design;

FIG. 2 is a front view of the second image thereof;

FIG. 3 is a front view of the third image thereof;

FIG. 4 is a front view of the fourth image thereof;

FIG. 5 is a front view of the fifth image thereof;

FIG. 6 is a front view of the sixth image thereof;

FIG. 7 is a front view of the seventh image thereof;

FIG. 8 is a front view of the eighth image thereof;

FIG. 9 is a front view of the ninth image thereof; and,

FIG. 10 is a front view of the tenth image thereof.

The appearance of the image transitions sequentially between the images shown in FIGS. 1-10. The process or period in which an image transitions to another forms no part of the claimed design. The broken line showing a display screen or portion thereof and graphical elements within the display screen are not part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with an animated graphical user interface, as shown and described. 